Autogru Rigo few years ago introduced on the crane market a 50 metric tons capacity rough-terrain crane, called RT 500, with 35 meter fully hydraulic and proportional boom length and hydrostatic transmission.
The advantages of this transmission are clear and easy to understand: the carrier of the machine becomes a simple box structure with internal steel stiffening ribs. This constitutes an extremely rigid element which is an ideal torsion resistant structure, lighter and stronger than traditional carriers. The RT 500 GVW is 32,5 tons and its carrier only 2,55 meter wide! So standard trailers are enough to transport this unit, without incurring in higher costs for special over-size vehicles.
This carrier enables the crane to have a real 360° lifting chart, due to the components location on the superstructure which also simplify maintenance operations. In fact, the diesel engine and hydraulic pumps are all located in the superstructure, where they can be easily serviced when needed. In case of machine malfunction, when there is a problem in the diesel engine or in the transmission, the downtime of replacing a component such as hydraulic pump or motor is much shorter of that if the torque converter or pumps had to be dismantled and then put it back on. It is easy to imagine the large space around the engine and other components that are located on the upper part, where they can be easily reached.
On the other hand, on traditional rough-terrain cranes, the transmission (torque converter) is coupled directly to the diesel engine; both components are located on the rear side of the carrier, confined in a tight area, not easily accessible. Another technical feature of the RT 500, is its boom proportional telescoping system. The operator can select to extend the boom section according to 2 main programs using the ideal boom configuration according to the load he is lifting.